Abstract: Objective The aim of this study was to investigate the implication of miR-139 in hepatocellular carcinoma（HCC） and the bioinformatics analysis of its perimentally validated targets genes. Methods By analyzing the data of HCC in The Cancer Genome Atlas（TCGA） database，we compared the miR-139 levels in HCC tissues and its adjacent liver tissues and analyzed the association between miR-139 levels with pathological stages and survivals of patients. We also retrieved the experimentally validated target genes from the mirTarBase database，and the gene ontology（GO） and the Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analysis were made. Results Levels of miR-139 in HCC tissues（143.12±117.55） was significantly lower than that in adjacent tissues 【（486.48±145.18），P<0.01】；The patients were stratified into 4 groups based on the levels of mir-139 and the median survival in each groups from low to high were 16.05 m，16.12 m，24.05 m and 24.19 m，respectively，and there was a significant difference among different groups （Log-rank，P<0.001）；Go function analysis revealed that miR-139 target genes were mainly regulating binding with promoters and intracellular signaling transduction and KEGG analysis indicated that these genes were mainly involved in cancer-related pathways，B and T cell receptor signaling and Ras signaling pathway. Conclusion miR-139 levels is down-regulated in HCC and is negatively correlated with pathological stages and survival of patients（both P<0.05）. Bioinformatics analysis suggest that miR-139 contributes to cancer development mainly through regulating gene transcription and cancer-related signaling pathways. The present study indicates that miR-139 plays an inhibitory role in formation and development of HCC.

Key words: Hepatoma, miR-139, The Cancer Genome Atlas, Gene ontology